Water Quality - Nutrient Management and Cropping Systems - Lesson 10 No-till Farming

Water Quality - Nutrient Management and Cropping Systems - Lesson 10 No-till Farming

Target Grade Level / Age Range:

Grades 9-12

Time:

50 minutes

Purpose:

Students will be able to identify the differences between conventional tillage and conservation tillage practices.

Students will understand how no-till farming can increase water absorption onto farm ground and help minimize soil and nutrient loss to water erosion.

Materials:

Suggested Companion Resources (books and websites)

Vocabulary (with definitions)

  • Conservation tillage: practices include no-till, reduced tillage, mulch tillage, ridge tillage, contour tillage
  • No-Till: By not tilling a field after harvesting or before planting the dead organic matter stays on the soil surface. This ‘litter’ can protect and hold the soil in place during a rainstorm allowing water to be absorbed more slowly and not letting it run off and carry soil with it. This involves land cultivation with little or no soil surface disturbance, the only disturbance being during planting while minimum tillage means reduced level of soil manipulation involving ploughing using primary tillage implements.
  • Reduced or minimum tillage: cultivation systems not otherwise defined that leave at least 30% of the residue on the soil surface
  • Mulch tillage: the soil is prepared or tilled in such a way that the plant residues or other materials are left to cover the surface to a maximum extent.
  • Ridge tillage: involves planting crops in rows either along both sides or on top of the ridges which are prepared at the commencement of the cropping season.
  • Contour tillage: When tillage is at right angles to the direction of the slope
  • Strip or zonal tillage: the seedbed is divided into a seedling zone and a soil management zone. the seedling zone (5 to 10 cm wide) is mechanically tilled to optimize the soil and micro-climate environment for germination and seedling establishment. The interrow zone is left undisturbed and protected by mulch. Strip tillage can also be achieved by chiseling in the row zone to assist water infiltration and root proliferation.

Background – Agricultural Connections (what would a teacher need to know to be able to teach this content)

Farmers have a vested interest in keeping soil healthy to raise better crops and to have access to clean water supplies for their livestock. And we all probably care about wildlife and natural ecosystems. Fish and other aquatic animals need clean water as habitat just like you and I need clean air to breathe.

We all play a role in caring for our soil and water. Here in Iowa, the Department of Agriculture and Land Stewardship, the Department of Natural Resources and Iowa State University are leading the Nutrient Reduction Strategy that will use a science driven approach to reduce nutrients (primarily nitrogen and phosphorus) in surface water from point and non-point sources. Farmers are charged with using more precise methods in applying fertilizer as well as adopting other practices that in some cases can significantly reduce the nutrients that run off fields or that are leached through the soil and into waterways. But, urban residents and commercial industries also play a part in this because water pollutants don’t only come from farms.

Interest Approach or Motivator

Divide the class into five groups. Give each group a Splash Zone Target, eyedropper, and a small container of water. Instruct student to put enough soil (about ½ teaspoon of dry soil) in the center of their target to just cover the center circle. Fill the eyedropper with water. Hold the eyedropper about 18 inches (or 46 cm) above the soil sample.

Drop 5 drops of water directly onto the soil sample. If a drop misses the soil, continue until 5 drops hit the soil. Record the number of water “splashes”—drops containing soil—in each zone. Complete the graph to show your results.

Discuss the following questions:

  1. What did you observe? How did the soil particles move from the center of the target? (they were picked up and moved with the water)
  2. Which zone contained the most number of water drops with soil particles? Why?
  3. Which zone contained the least number? Why?
  4. What would happen if the drops were larger? (splashes would travel further)
  5. How might you prevent splash erosion? (plant vegetation, cover the soil with mulch)
  6. How do farmers decide which erosion control methods to use? (it depends on the slope, soil types, and what he or she wants to plant)

    Note: You may want to repeat this activity with drops from 1 meter high or try the activity with wet soil.

Procedures

Objective 1
  1. ****Prior to class**** Write each of the vocabulary words on a separate note card. Write each of the definitions on a separate note card. Hide all 14 note cards around the classroom. Get creative and tape them under chairs or tables, behind doors, high, low, etc.
  2. Go-get-it moment. Instruct students that there are 14 note cards hidden around the room. Their task is to 1) work together to find all 14 cards 2) work together to match each vocabulary word with the correct definition. (NOTE: this works well with groups of approximately 10-12. If you have more students, consider dividing the class in two or three groups. Make two or three sets of the note cards using different colored note cards. Instruct each group to only find their assigned colored note card.)
  3. Monitor student progress. Allow approximately 3 minutes for the note card search and another 5 minutes for matching of the definitions. Once all cards have been found and matched. Present slides 2-10 in the accompanying PowerPoint. On each slide have representatives from each group share the vocabulary word and the definition. Have students capture pertinent information into their notebooks – possibly writing their own definitions defining the vocabulary words.
Objective 2
  1. Hand out copies of the Iowa Farm and Rural Life Poll. Ask students to read starting on page 1 “Conservation practice use” through page 5. Students should stop reading before “Monarch butterfly conservation”. What tillage conservation practices are farmers using? Show slide 11 in the accompanying PowerPoint.
  2. How does that compare to previous practices? Show slide 12 in the accompanying PowerPoint.
  3. What are some of the benefits of using conservation tillage? Show slides 13-14 in the accompanying PowerPoint. Have students capture key points into their notebooks.
    1. Reduces labor, saves time: As little as one trip for planting compared to two or more tillage operations means fewer hours on a tractor and fewer labor hours to pay ... or more acres to farm. For instance, on 500 acres the time savings can be as much as 225 hours per year. That’s almost four 60-hour weeks.
    2. Saves fuel:  Save an average 3.5 gallons an acre or 1,750 gallons on a 500-acre farm.
    3. Reduces machinery wear: Fewer trips save an estimated $5 per acre on machinery wear and maintenance costs—a $2,500 savings on a 500-acre farm.
    4. Improves soil tilth: A continuous no-till system increases soil particle aggregation (small soil clumps) making it easier for plants to establish roots. Improved soil tilth also can minimize compaction. Of course, compaction is also reduced by reducing trips across the field.
    5. Increases organic matter: The latest research shows the more soil is tilled, the more carbon is released to the air and the less carbon is available to build organic matter for future crops. In fact, carbon accounts for about half of organic matter.
    6. Traps soil moisture to improve water availability: Crop residue traps water in the soil by providing shade. The shade reduces water evaporation. Residue acts as tiny dams slowing runoff and increasing the opportunity for water to soak into the soil. Infiltration increases by the channels (macropores) created by earthworms and old plant roots. Continuous no-till can result in as much as two additional inches of water available to plants in late summer.
    7. Reduces soil erosion: Crop residues on the soil surface reduce erosion by water and wind. Depending on the amount of residues present, soil erosion can be reduced by up to 90% compared to an unprotected, intensively tilled field.
    8. Improves water quality: Crop residue helps hold soil along with associated nutrients (particularly phosphorous) and pesticides on the field to reduce runoff into surface water. In fact, residue can cut herbicide runoff rates in half. Additionally, microbes that live in carbon-rich soils quickly degrade pesticides and utilize nutrients to protect groundwater quality.
    9. Increases wildlife: Crop residues provide shelter and food for wildlife, such as game birds and small animals.
    10. Improves air quality: Crop residue left on the surface improves air quality because it: Reduces wind erosion, thus it reduces the amount of dust in the air; Reduces fossil fuel emissions from tractors by making fewer trips across the field; and Reduces the release of carbon dioxide into the atmosphere by tying up more carbon in organic matter.
  4. Have the students read two or more of the following articles. Then have students write a persuasive letter to a farmer encouraging them to implement conservation tillage practices on their farm. Students can also assume that the farmer is already using conservation tillage and write a persuasive letter on how they should improve or refine their conservation tillage practices. Be sure to use correct letter formatting. (See the WikiHow link to writing a friendly letter.)  Students can turn in their letter before leaving class or complete it as homework.
    1. No-till agriculture offers vast sustainability benefits. So why do many organic farmers reject it? https://www.geneticliteracyproject.org/2016/06/02/no-till-agriculture-offers-vast-sustainability-benefits-so-why-do-organic-farmers-reject-it/
    2. Pros and Cons of no-tillage farming: http://greentumble.com/pros-and-cons-of-no-tillage-farming/
    3. No-till Study Showing Benefits, if Farmers Stick with It: https://www.agweb.com/article/no-till-study-showing-benefits-if-farmers-stick-with-it-apnews/
    4. Could No-Till Farming Reverse Climate Change?: https://www.usnews.com/news/articles/2016-08-04/could-no-till-farming-reverse-climate-change

Essential Files (maps, charts, pictures, or documents)

Did you know? (Ag facts)

  • The most recent Census of Agriculture found no-tilled acres in the U.S. reached a new high of 96 million acres in 2012
  • Nearly 35% of cropland acres in the U.S. are no-tilled and more than 10 million acres of cover crops have been seeded across the country
  • As of 2012, there were more than 389 million acres of total cropland in the U.S. and 279 million tillable acres, with 96 million acres falling under no-till practices — up from about 88 million acres that the USDA’s Economic Research Service (ERS) estimated in 2010
  • Another 76 million acres — or 27% of the U.S. total crop acres — fell under “conservation tillage.” This means 173 million acres — or 62% — of U.S. tillable acres saw some type of conservation tillage practice when the Census was taken.
  • The Census found that no-till was practiced on 278,290 farms, conservation tillage on 195,738 farms and conventional tillage on 405,692 operations.
  • Forty years ago, there were 3.3 million acres of no-till in the U.S., and the total has grown by an average of 2.3% annually since that year

Extension Activities (how students can carry this beyond the classroom)

  • As time allows students could read their letters to the class.
  • Post the persuasive letters around the classroom. Do a ‘gallery-walk’ and have students walk around the room reading each other’s work.
  • Identify farmers in the community that you could mail the letters to.
  • Have the students share the letters with their local farm bureau, commodity organization meeting, NRCS office, soil and water conservation district meeting, or other public event.

Sources/Credits

Lesson plan development was funded by the Resource Enhancement and Protection Conservation Education Program (REAP CEP). Resource Enhancement and Protection Program (REAP): Invest in Iowa our outdoors, our heritage, our people. REAP is supported by the state of Iowa, providing funding to public and private partners for natural and cultural resources projects, including water quality, wildlife habitat, soil conservation, parks, trails, historic preservation and more.

Author(s)

Will Fett

Organization Affiliation

Iowa Agriculture Literacy Foundation

National Agriculture Literacy Outcomes

  • T1.9-12.e. Evaluate the potential impacts of climate change on agriculture
  • T1.9-12.f. Evaluate the various definitions of “sustainable agriculture,” considering population growth, carbon footprint, environmental systems, land and water resources, and economics

Iowa Core Standards

  • HS-LS2-4. Use mathematical representations to support claims for the cycling of matter and flow of energy among organisms in an ecosystem. (no-till, cover crops)
  • HS-LS2-7. Design, evaluate, and refine a solution for reducing the impacts of human activities on the environment and biodiversity. * (no-till, buffer zones, riparian area management, bioreactors)
  • HS-ESS3-1. Construct an explanation based on evidence for how the availability of natural resources, occurrence of natural hazards, and changes in climate have influenced human activity. (till v. no-till, cover cropping)